This invention relates to a fluid pump provided with a novel valve element, for use particularly, but not exclusively, with a soap dispenser.
A fluid dispensing device can be provided with a pump comprising a fluid inlet, a priming cylinder with a piston, a fluid outlet, and a valve element disposed between the fluid inlet and the fluid outlet. The valve element is adapted to seal the fluid outlet when the cylinder is primed with fluid, and to seal the fluid inlet when said fluid is driven from the cylinder.
In one arrangement a conical flexible valve element is provided, which is disposed in compression between a relatively large inlet aperture, and a relatively small outlet aperture. The periphery of the valve element surrounds the inlet aperture, and the apex of the valve element is seated in the outlet aperture, thereby creating an inlet and an outlet seal. In use the periphery of the valve element is drawn away from the inlet aperture, and the apex is pressed into the outlet aperture when the cylinder is primed with fluid, and the periphery of the valve element is pressed against the surface around the inlet aperture, and the apex is drawn away from the outlet aperture, when said fluid is driven form the cylinder.
The valve element must be provided with a particular rigidity in order to provide adequate seals, and in particular to maintain one seal when the other is opened. As a result, a relatively large force may be required to manipulate the valve element as described above. This can put a strain on associated parts of a pump and reduce its life span.